Light emitting device array and backlight unit

ABSTRACT

A light emitting device array includes a substrate including a first region and a second region that is inclined with respect to the first region, a first light emitting device package arranged on the first region, and a second light emitting device package that is arranged on the second region and is inclined with respect to the first light emitting device package at an inclination angle between 90° and 160°.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Korean PatentApplication No. 10-2011-0067408, filed on Jul. 7, 2011 in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference.

BACKGROUND

1. Field

Embodiments relate to a light emitting device array and a backlightunit.

2. Description of the Related Art

Light Emitting Diodes (LEDs) are devices that convert electrical signalsinto light using characteristics of compound semiconductors and are usedin home appliances, remote controls, electronic scoreboards, displays,various automated devices, and the like and the application range ofLEDs continues to expand.

A backlight unit which employs LEDs may be used in a display device suchas a liquid crystal display device and may also be used in lightingdevices in other fields. A generally used backlight unit includes alight source, a light guide plate that diffuses light generated by thelight source, and optical sheets that function to spread or focus lightemitted from the light guide plate.

LEDs that are driven at low voltage and are highly efficient may beapplied as the light source of the backlight unit. The LED is a2-terminal diode including a compound semiconductor such as galliumarsenide (GaAs), Gallium Nitride (GaN), or indium gallium nitride(InGaN). When voltage is applied to the cathode and anode terminals ofthe LED, the LED emits visual light with light energy generated whenelectrons and holes are combined.

The backlight unit is classified into an edge type and a direct typedepending on the position of the light source.

Edge type backlight units are generally applied to relatively smallliquid crystal display devices such as monitors of laptop computers anddesktop computers and have advantages in that the backlight unitsprovide highly uniform light and have a long life and also contribute toachieving a slim liquid crystal display device.

When a backlight unit employing light emitting devices is configured,there is a need to guide light generated by the light emitting devicesin a specific direction and to guarantee uniform emission over thedisplay area of the backlight unit. In addition, it is also an importantissue to achieve a slim and light backlight unit in order to improveproductivity and increase user convenience.

SUMMARY

In one embodiment, a light emitting device array includes a substrateincluding a first region and a second region that is inclined withrespect to the first region, a first light emitting device packagearranged on the first region, and at least one second light emittingdevice package that is arranged on the second region and is inclinedwith respect to the first light emitting device package at aninclination angle between 90° and 160°.

In another embodiment, a backlight unit includes a light guide plate,and at least one light emitting device array arranged adjacent to acorner of the light guide plate which corresponds to an edge of one sidesurface of the light guide plate, the light emitting device arraycomprising a substrate including a first region and a second region thatis inclined with respect to the first region, a first light emittingdevice package arranged on the first region, and at least one secondlight emitting device package that is arranged on the second region andis inclined with respect to the first light emitting device package atan inclination angle between 90° and 160°.

BRIEF DESCRIPTION OF THE DRAWINGS

Details of embodiments will be more clearly understood from thefollowing detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is an exploded perspective view schematically illustrating alight emitting device module including an array of light emittingdevices according to an embodiment;

FIG. 2 is a perspective view of a first light emitting device packageshown in FIG. 1;

FIG. 3 is an enlarged view of a first embodiment of a ‘P’ block shown inFIG. 1;

FIG. 4 is an enlarged view of a second embodiment of the ‘P’ block shownin FIG. 1;

FIG. 5 illustrates a light emitting device array according to anotherembodiment;

FIG. 6A is an exploded perspective view of a backlight unit according toone embodiment;

FIGS. 6A to 6E are partial cross-sectional views of the backlight unitaccording to an embodiment;

FIG. 7A is a partial cross-sectional view of a backlight unit accordingto an embodiment;

FIG. 7B is a partial cross-sectional view of a backlight unit accordingto an embodiment;

FIG. 7C is a partial cross-sectional view of a backlight unit accordingto an embodiment;

FIG. 8 is a perspective exploded view of a liquid crystal display deviceincluding a backlight unit according to an embodiment; and

FIG. 9 is a cross-sectional view of an electronic device including abacklight unit (not shown) according to an embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

In the description of the embodiments, it will be understood that, whena layer (or film), a region, a pattern, or a structure is referred to asbeing “on” or “under” another substrate, another layer (or film),another region, another pad, or another pattern, it can be “directly” or“indirectly” over the other substrate, layer (or film), region, pad, orpattern, or one or more intervening layers may also be present. Such aposition of the layer has been described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated,omitted, or schematically illustrated for convenience of description andclarity. Also, the size of each constituent element does not entirelyreflect the actual size thereof.

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings.

FIG. 1 is an exploded perspective view schematically illustrating alight emitting device module including an array of light emittingdevices according to an embodiment.

As shown in FIG. 1, a light emitting device module 200 includes a powercontrol module 210, a light emitting device array 100, and a connector130.

The power control module 210 may include a power supply 212 thatgenerates power that is consumed by a first light emitting devicepackage 110 embedded in the light emitting device array 100, a controlunit 214 that controls operation of the power supply 212, and aconnector connection portion 216 connected to one end of the connector130.

Here, the power supply 212 operates under control of the control unit214 and generates power that is consumed by the light emitting devicearray 100.

The control unit 214 may control operation of the power supply 212according to an externally input command.

The externally input command may be, but is not limited to, a commandoutput from an input device (not shown) directly connected to the lightemitting device module 200 or a command output from a remote controlthat is used to control operation of an apparatus including the lightemitting device module 200.

The connector connection portion 216 is connected to one end of theconnector 130 and may provide power supplied from the power supply 212to the connector 130.

The light emitting device array 100 may include a first light emittingdevice package 110 and a plurality of second light emitting devicepackages 111 to 116, a substrate 120, on which the first light emittingdevice package 110 and the plurality of second light emitting devicepackages 111 to 116 are provided, and a connector terminal 122 that isformed on the substrate 120 and is connected to the other end of theconnector 130.

Here, the connector terminal 122 may be electrically connected to theconnector connection portion 216 through the connector 130.

The substrate 120 may be a printed circuit board (PCB), a flexibleprinted circuit board, or a metal board. When the substrate 120 is aPCB, the substrate 120 may be a single-sided PCB, a double-sided PCB, amulti-layer PCB, or the like. The embodiments will be described belowwith reference to an example in which the substrate 120 is asingle-sided PCB although the substrate 120 is not limited to thesingle-sided PCB.

The first and the plurality of second light emitting device packages 110to 116 may be, but are not necessarily, divided into a plurality ofgroups (not shown) and may be, but are not necessarily, connected inseries or in parallel.

Although the number of the first and the plurality of second lightemitting device packages 110 to 116 shown in FIG. 1 is 7, there is nolimitation as to the total number of the first and the plurality ofsecond light emitting device packages 110 to 116.

At least two of the first and the plurality of second light emittingdevice packages 110 to 116 may, but not necessarily, emit light ofdifferent colors or light of the same color.

For example, in the case in which the first and the plurality of secondlight emitting device packages 110 to 116 emit white light, the firstand the plurality of second light emitting device packages 110 to 116may be implemented using light emitting device packages that emit redlight and light emitting device packages that emit blue light. Thus,light emitting device packages that emit red light and light emittingdevice packages that emit blue light may be alternately mounted. Thefirst and the plurality of second light emitting device packages 110 to116 that emit white light may also be implemented using light emittingdevice packages that emit red light, light emitting device packages thatemit blue light, and light emitting device packages that emit greenlight.

The first and the plurality of second light emitting device packages 110to 116 may, but not necessarily, have the same configuration and atleast one thereof may, but not necessarily, include a plurality of lightemitting devices (not shown). Each of the first and the plurality ofsecond light emitting device packages 110 to 116 may be a side view typeof light emitting device package that emits light from the side surfacesthereof.

The following description is given with reference to the case in whichthe first and the plurality of second light emitting device packages 110to 116 have the same configuration.

FIG. 2 is a perspective view of the first light emitting device packageshown in FIG. 1.

The first light emitting device package 110 shown in FIG. 2 has the sameconfiguration as the second light emitting device packages 111 to 116and at least one of the color of a fluorescent substance of the firstlight emitting device package 110 and the color of light emitted from alight emitting device of the first light emitting device package 110 maybe different from that of the second light emitting device packages 111to 116.

The first light emitting device package 110 may include a light emittingdevice 11 and a body 12 on which the light emitting device 11 isprovided.

The body 12 may be formed of at least one of a resin substance such aspolyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride(AlN), AlOx, liquid polymer, photo sensitive glass (PSG), polyamide 9T(PA9T), syndiotactic polystyrene (SPS), a metallic substance, sapphire(Al2O3), beryllium oxide (BeO), ceramic, and a printed circuit board(PCB).

The body 12 may be, but is not necessarily, formed using injectionmolding, etching, and the like.

A top surface of the body 12 may have various shapes that include, butare not limited to, a triangle, a rectangle, a polygon, and a circle.

The body 12 may have a cavity s in which the light emitting device 11 isarranged, a cross-sectional shape of the cavity s may be a cup, aconcave bowl, or the like, and an inner surface of the body 12 thatdefines the cavity s may be formed obliquely in a downward direction.

The cavity s may have various plane shapes that include, but are notlimited to, a circle, a quadrangle, a polygon, and an oval.

First and second lead frames 13 and 14 may be arranged on a lowersurface of the body 12 and the first and second lead frames 13 and 14may include one or more substance or alloy from among, for example,titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chrome (Cr),tantalum (Ta), platinum (Pt), tin (Sn), silver (Ag), phosphorous (P),aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si),germanium (Ge), hafnium (Hf), ruthenium (Ru), and iron (Fe).

Each of the first and second lead frames 13 and 14 may be, but is notnecessarily, formed in a single layer or multi-layer structure.

An inner surface of the body 12 may be formed obliquely at aninclination angle with respect to one of the first and second leadframes 13 and 14 and a reflection angle of light emitted from the lightemitting device 11 may vary according to the inclination angle, therebyenabling control of the beam angle (or beam range) of externally emittedlight. The degree of concentration of light externally emitted from thelight emitting device 11 increases as the beam angle of the externallyemitted light decreases and decreases as the beam angle increases.

The inner surface of the body 12 may, but is not necessarily, have aplurality of inclination angles.

The first and second lead frames 13 and 14 may be electrically connectedto the light emitting device 11 and connected respectively to positiveand negative poles of an external power source (not shown) to supplypower to the light emitting device 11.

The light emitting device 11 may be mounted on the first lead frame 13.The light emitting device 11 may be die-bonded to the first lead frame13 and may be wire-bonded to the second lead frame 14 through a wire(not shown) to receive power from the first and second lead frames 13and 14.

Here, the light emitting device 11 may be, but is not limited to,wire-bonded or die-bonded to the first and second lead frames 13 and 14.

A cathode mark (not shown) may be formed on the body 12. The cathodemark may serve to discriminate the poles of the light emitting device11, i.e., the poles of the first and second lead frames 13 and 14, toprevent confusion when electrically connecting the first and second leadframes 13 and 14.

The light emitting device 11 may be a light emitting diode (LED). TheLED may be, but is not necessarily, a color LED that emits, for example,red, green, blue, or white light or an ultraviolet (UV) LED that emitsultraviolet light. A plurality of light emitting devices 11 may bemounted on the first lead frame 13 and at least one light emittingdevice 11 may be mounted on the first and second lead frames 13 and 14although there is no limitation as to the number of the light emittingdevices 11 and the mounting position thereof.

The embodiments are described below with reference to the case in whichthe light emitting device 11 is a blue light emitting device that emitsblue light.

The body 12 may include a resin substance 17 that fills the cavity s.That is, the resin substance 17 may be, but is not necessarily, formedin a double-molding structure or a triple-molding structure.

The resin substance 17 may be formed in the shape of a film and mayinclude at least one of a fluorescent substance and an optical diffusionsubstance and may also include a translucent substance that does notinclude a fluorescent substance and an optical diffusion substancealthough there is no limitation as to the shape and composition of theresin substance 17.

In an embodiment, the resin substance 17 may include first and secondfluorescent substances 15 and 16 and may be mixed with a siliconsubstance (not shown) or may be formed in a double structure althoughthere is no limitation as to the formation or composition of the resinsubstance 17.

Specifically, in the case in which the first light emitting devicepackage 110 emits white light, the first and second fluorescentsubstances 15 and 16 may be a red fluorescent substance and a greensubstance because of the light emitting device 11 that emits blue light.

Although the embodiment has been described with reference to the case inwhich the resin substance 17 includes the first and second fluorescentsubstances 15 and 16, the resin substance 17 may include a fluorescentsubstance of single color which may be, but is not limited to, a yellowfluorescent substance.

In the case in which the light emitting device 11 emits red or greenlight, the first light emitting device package 110 may include a mixtureof a blue fluorescent substance and a green fluorescent substance or amixture of a blue fluorescent substance and a red fluorescent substanceto emit white light.

FIG. 3 is an enlarged view of a first embodiment of a ‘P’ block shown inFIG. 1.

As shown in FIG. 3, the light emitting device array 100 according to anembodiment may include a first light emitting device package 110, aplurality of second light emitting device packages 111 and 112, and asubstrate 120 on which the first and the plurality of second lightemitting device packages 110 to 112 are arranged.

The plurality of second light emitting device packages 110 to 112 mayhave the same package size and embodiments are described below withreference to the case in which the plurality of second light emittingdevice packages 110 to 112 have the same configuration.

Here, the first light emitting device package 110 may be arrangedadjacent to one edge of the substrate 120. The edge may have a bentportion and the first light emitting device package 110 may be arrangedobliquely according to the bent portion.

That is, the first light emitting device package 110 may be inclined atan inclination angle θ with respect to the second light emitting devicepackage 111 that is arranged adjacent to the first light emitting devicepackage 110.

The inclination angle θ may be in a range of 90° to 160°. When theinclination angle θ is less than 90°, a beam range (or beam angle) (notshown) of light emitted from a light emitting surface of the first lightemitting device package 110 is directed toward side surfaces and lightemitting surfaces of the plurality of second light emitting devicepackages 111 and 112, thus generating a dark zone at the edge. When theinclination angle θ is greater than 160°, the beam range (or beam angle)(not shown) of light emitted from the light emitting surface of thefirst light emitting device package 110 does not greatly differ frombeam ranges (not shown) of the plurality of second light emitting devicepackages 111 and 112 and therefore it is not possible to reduce thetotal number of light emitting device packages arranged on the substrate120.

Here, a first separation distance b1 between the first light emittingdevice package 110 and the second light emitting device package 111arranged adjacent thereto may be allowed to be equal to or longer than asecond separation distance b2 between the plurality of second lightemitting device packages 111 and 112.

That is, the first separation distance b1 may be changed according tothe inclination angle θ and may be inversely proportional to theinclination angle θ.

For example, the first separation distance b1 may be equal to the secondseparation distance b2 when the inclination angle θ is 160° and may belonger than the second separation distance b2 when the inclination angleθ is 90°.

As described above, the second light emitting device packages 111 and112 are spaced from each other by the second separation distance b2 andthe separation distance between each of the second light emitting devicepackages 114, 115, and 116 may be equal to the second separationdistance b2 as shown in FIG. 1.

When the light emitting device packages of the light emitting devicearray 100 illustrated in the first embodiment have the same packagesize, the first separation distance b1 between the first and secondlight emitting device packages 110 and 111 may be changed according tothe inclination angle θ between the first and second light emittingdevice packages 110 and 111.

FIG. 4 is an enlarged view of a second embodiment of a ‘P’ block shownin FIG. 1.

The same reference numbers as those of FIG. 3 are used for FIG. 4 andportions of the second embodiment similar to the first embodiment arenot described or are briefly described below.

As shown in FIG. 4, the light emitting device array 100 according to anembodiment may include a first light emitting device package 110, aplurality of second light emitting device packages 111 and 112, and asubstrate 120 on which the first light emitting device package 110 andthe plurality of second light emitting device packages 111 and 112 arearranged.

Here, the first light emitting device package 110 may have a differentpackage size from the second light emitting device packages 111 and 112.

That is, the first light emitting device package 110 may have a firstpackage size a1 and the second light emitting device packages 111 and112 may have a second package size a2 that is less than the firstpackage size a1.

The first light emitting device package 110 may be inclined at aninclination angle θ with respect to the second light emitting devicepackage 111 that is arranged adjacent to the substrate 120.

The inclination angle θ may be in a range of 90° to 160°. When theinclination angle θ is less than 90°, a beam range (or beam angle) (notshown) of light emitted from a light emitting surface of the first lightemitting device package 110 is directed toward side surfaces and lightemitting surfaces of the second light emitting device packages 111 and112 to generate a blind zone at the edge. When the inclination angle θis greater than 160°, the beam range (or beam angle) (not shown) oflight emitted from the light emitting surface of the first lightemitting device package 110 does not greatly differ from beam ranges(not shown) of the second light emitting device packages 111 and 112 andtherefore it is not possible to reduce the total number of lightemitting device packages arranged on the substrate 120.

Here, a first separation distance b1 between the first and second lightemitting device packages 110 and 111 may be longer than a secondseparation distance b2 between the plurality of second light emittingdevice packages 111 and 112.

That is, the first separation distance b1 may be changed according tothe inclination angle θ and the first and second package sizes a1 and a2and may be inversely proportional to the inclination angle θ and may beproportional to at least one of the first and second package sizes a1and a2.

However, the difference between the first and second separationdistances b1 and b2 may be maximized when the inclination angle θ is160° and may be minimized when the inclination angle θ is 90°.

The second and third light emitting device packages 111 and 112 arespaced from each other by the second separation distance b2 and theseparation distance between each of the fifth, sixth, and seventh lightemitting device packages 114, 115, and 116 may be equal to the secondseparation distance b2 as shown in FIG. 1.

In the light emitting device array 100 illustrated in the secondembodiment, the first separation distance b1 between the first lightemitting device package 110 having the first package size a1 and thesecond light emitting device package 111 that is adjacent to the firstlight emitting device package 110 and that has the second package sizea2 may be changed according to the first package size a1 and theinclination angle θ.

FIG. 5 illustrates a light emitting device array 200 according toanother embodiment.

As shown in FIG. 5, the light emitting device array 200 according tothis embodiment may include a first light emitting device package 210, asecond light emitting device package 211, and a substrate 220 on whichthe first light emitting device package 210 and the second lightemitting device package 211 are arranged.

The substrate 220 may include a first region 222 and a second region 224that are formed in a bent shape and the first region 222 and the secondregion 224 may be inclined with respect to each other.

The first light emitting device package 210 may be arranged on the firstregion 222 and the second light emitting device package 211 may bearranged on the second region 224. The first light emitting devicepackage 210 and the second light emitting device package 211 which emitwhite light may be implemented using a light emitting device packagethat emits red light and a light emitting device package that emits bluelight. Thus, light emitting device packages that emit red light andlight emitting device packages that emit blue light may be alternatelymounted. The light emitting device packages that emit white light mayalso be implemented using light emitting device packages that emit redlight, light emitting device packages that emit blue light, and lightemitting device packages that emit green light.

Each of the first and second light emitting device packages 210 and 211may be of a top view type that emits light upwardly.

The substrate 220 may have a plurality of bent portions. When thesubstrate 220 has two bent portions, the substrate 220 may include afirst region, a second region, and a third region and a light emittingdevice package may be arranged on each of the regions.

FIG. 6A is an exploded perspective view of a backlight unit 300according to one embodiment and FIGS. 6A to 6E are partialcross-sectional views of the backlight unit 300 according to anotherembodiment.

As shown in FIG. 6A, the backlight unit 300 according to the embodimentis of an edge-light type and includes a light emitting device array 310and a light guide plate 320. The light emitting device array 310includes a substrate 316 and a light emitting device array 310. Thesubstrate 316 is arranged adjacent to a corner (or corner edge) of thelight guide plate 320, which corresponds to an edge of one side surfaceof the light guide plate 320, and has a bent portion 314 so as to forman inclination angle in a range of 90° to 160°. The light emittingdevice array 310 includes light emitting device packages 312 that arearranged on a portion of the substrate 316 which faces the light guideplate 320.

The backlight unit 300 is a means for providing light to a liquidcrystal display device (not shown) and may be located at the rear sideof the liquid crystal display device (not shown). The backlight unit 300may provide light with high brightness and an appropriate viewing angleto the liquid crystal display device (not shown).

The light emitting device packages 312 may be provided on the substrate316. The light emitting device packages 312 may be electricallyconnected to the substrate 316. The light emitting device packages 312may receive power from the outside and generate and provide light to thelight guide plate 320. Although the light emitting device packages 312may be provided in one array on the substrate 316, there is nolimitation as to how the light emitting device packages 312 are arrayedon the substrate 316 and the light emitting device packages 312 may beprovided in several arrays on the substrate 316. The light emittingdevice packages 312 may be mounted on the substrate 316 so as to form aninclination angle and may be arranged thereon in an arbitrary form.

The light emitting device array 310 includes the substrate 316 and thelight emitting device packages 312, and the light emitting devicepackages 312 may be arranged on the substrate 316 in the mannerdescribed above in the embodiment of FIG. 5.

The light emitting device packages 312 may simultaneously provide lightto a plurality of side surfaces of the light guide plate 320. The lightemitting device packages 312 can prevent generation of a dark zone atthe corner of the light guide plate 320. The light emitting devicepackages 312 may provide light to one corner of the light guide plate320 according to an embodiment.

A further detailed description of the light emitting device packages 312is omitted herein since the light emitting device packages 312 havealready been described above in detail with reference to FIG. 2.

The substrate 316 may be formed of a high heat protection substance. Thesubstrate 316 may be formed obliquely at an inclination angle. Thesubstrate 316 may be bendable. One portion of the substrate 316 may bebendable. One portion of the substrate 316 may be bent into anapproximately L shape. The light emitting device packages 312 may beprovided on one surface of the substrate 316. The surface of thesubstrate 316 on which the light emitting device packages 312 areprovided may face one side surface of the light guide plate 320.

As shown in FIG. 6B, the substrate 316 may be bent at one portion of thelongitudinal axis. The substrate 316 may be provided with the lightemitting device packages 312 at both sides of the bent portion 314.Thus, the substrate 316 can provide light to side surfaces of the lightguide plate 320.

When the top surface of the light guide plate 320 is approximatelysquare, the substrate 316 may be bent at a middle portion of thelongitudinal axis such that the bent portion 314 is located at onecorner of the light guide plate 320 which corresponds to an edge of oneside surface of the light guide plate 320.

The bent portion 314 of the substrate 316 may be provided at one cornerof the light guide plate 320. The substrate 316 may be formed so as tosurround a portion of the corner of the light guide plate 320. Thesubstrate 316 may face one side surface of the light guide plate 320.The substrate 316 may also simultaneously face two side surfaces of thelight guide plate 320.

As shown in FIG. 6C, the substrate 316 according to another embodimentmay be bent at two portions. The substrate 316 may include a lightemitting device package 312 between the two bent portions 314. Thesubstrate 316 may be provided such that the light emitting devicepackage 312 provided between the two bent portions 314 of the substrate316 faces a corner of the light guide plate 320 which corresponds to anedge of one side surface of the light guide plate 320.

For example, the substrate 316 may include a first region 31, a secondregion 32, and a third region 33.

The first region 31 may be inclined at an angle between 90° and 160°with respect to the second region 32 that is connected to one end of thefirst region 31. The first region 31 may also be inclined at an anglebetween 90° and 160° with respect to the third region 33 that isconnected to the other end of the first region 31.

A first light emitting device package may be arranged on the firstregion 31, a second light emitting device package may be arranged on thesecond region 32, and a third light emitting device package may bearranged on the third region 33. Although the first light emittingdevice package, the second light emitting device package, and the thirdlight emitting device package may be the same light emitting devicepackages 312, the first to third light emitting device packages may havedifferent sizes or may emit light of different colors in someembodiments.

The light emitting device package(s) provided on the second region 32may emit light to a corner of the light guide plate 320.

The substrate 316 may have one bent portion that is provided at onecorner of the light guide plate 320 to eliminate a dark zone that couldbe generated when light are not provided to the corners of the lightguide plate 320.

The substrate 316 may be provided at one corner of the light guide plate320 which corresponds to an edge of one side surface of the light guideplate 320. The substrate 316 may be provided so as to surround a portionof one corner of the light guide plate 320. The substrate 316 may beprovided such that an inner part of the bent portion 314 faces a cornerof the light guide plate 320 which corresponds to an edge of one sidesurface of the light guide plate 320.

As shown in FIG. 6D, the substrate 316 of the backlight unit 300according to an embodiment may have a multi-layer structure. The firstlayer 31 of the substrate 316 may include aluminum (Al). The substrate316 may be bendable due to inclusion of aluminum in the first layer 31.The substrate 316 may be formed in an L shape. The substrate 316 may bebendable such that the substrate 316 may be, but is not necessarily,bent into an L shape.

The first layer 31 may include aluminum (Al) as described above. Thefirst layer 31 may be bent. The first layer 31 may have high heatprotection. The first layer 31 may be bendable to provide manufacturingconvenience.

The first layer 31 may have a thickness between 300 μm and 500 μm. Whenthe thickness of the first layer 31 is less than 300 μm, the first layer31 may exhibit poor impact resistance due to such low thickness, causingmanufacturing difficulties and reducing heat protection. When thethickness of the first layer 31 is greater than 500 μm, the bendabilityof the first layer 31 may be reduced and the first layer 31 may be ahindrance to achieving a slim backlight unit 300.

The second layer 32 may be formed of an insulating substance. The secondlayer 32 may have high thermal conductivity. The second layer 32 may beformed using epoxy or silicon resin filled with thermally conductiveparticles in order to increase thermal conductivity of the substrate316. The second layer 32 may electrically separate the first layer 31and the third layer 33. The second layer 32 may block current flowing inthe first layer 31 from being provided to the third layer 33.

The third layer 33 may be formed of conductive metal. For example, thethird layer 33 may include copper (Cu). The third layer 33 may be formedso as to be very thin. The third layer 33 may provide electricity to thelight emitting device packages 312. The third layer 33 may be in contactwith the light emitting device packages 312. The third layer 33 mayinclude an electrode pattern (not shown). The electrode pattern (notshown) of the third layer 33 may be electrically connected to the lightemitting device packages 312. The third layer 33 may provide electricityto the light emitting device packages 312 through the electrode pattern(not shown).

The surface of the substrate 316 on which the light emitting devicepackages 312 are provided may face the light guide plate 320. Forexample, the substrate 316 may face one side surface of the light guideplate 320. The substrate 316 may provide electricity to the lightemitting device packages 312.

One side surface of the light guide plate 320 may face the surface ofthe substrate 316 on which the light emitting device packages 312 arearranged. The top and bottom surfaces of the light guide plate 320 mayhave an area larger than that of the side surfaces of the light guideplate 320. One side surface of the light guide plate 320 may receivelight from the light emitting device packages 312. A reflective patternof the light guide plate 320 may be formed on the bottom surface of thelight guide plate 320. The light guide plate 320 may also include areflective pattern layer (not shown) at the bottom surface.

The reflective pattern layer (not shown) may be arranged on the bottomsurface of the light guide plate 320. The reflective pattern layer (notshown) may be in the form of dots or lines. The reflective pattern layer(not shown) may be formed by spreading ink onto the light guide plate320 or by etching the light guide plate 320 although there is nolimitation as to the forming process or substance of the reflectivepattern layer.

A polymethylmethacrylate (PMMA) or transparent acrylic resin that isformed in a flat type or a wedge type may be used as the light guideplate 320. Although the light guide plate 320 may also be formed ofglass, there is no limitation as to the composition of the light guideplate 320. Since the strength of the transparent acrylic resin is high,the transparent acrylic resin is hardly deformed and has a small weightand high visible light transmittance. In an edge light type, the lightemitting device packages 312 are located at the external surface of thebacklight unit 300 such that edge portions of the backlight unit 300 maybe brighter than other portions. Since the light guide plate 320 hashigh visible light transmittance, it is possible to prevent thephenomenon that light passes through the backlight unit 300 unevenlyover the entire surface and brightness increases at the edge portions ofthe backlight unit 300.

The light guide plate 320 may convert light incident on the lightemitting device packages 312 into surface light. The bottom surface ofthe light guide plate 320 may be formed obliquely or an oblique patternmay be formed at the bottom surface of the light guide plate 320 tocause irregular reflection. The light guide plate 320 may generateuniform surface light using such reflection.

The reflective pattern (not shown) may be formed at the bottom surfaceof the light guide plate 320. The reflective pattern (not shown) maycause irregular reflection. The reflective pattern (not shown) may beformed into a specific shape taking into consideration the distancebetween the reflective pattern and the light emitting device packages312. The reflective pattern (not shown) may be formed by shaping thesurface of the light guide plate 320 or by spreading ink onto thesurface of the light guide plate 320 although there is no limitation asto how the reflective pattern is formed. The reflective pattern (notshown) may prevent light incident on the light guide plate 320 from thelight emitting device packages 312 from concentrating upon both ends ofthe surface of the light guide plate 320. The reflective pattern (notshown) may allow light to be uniformly emitted from the top surface ofthe light guide plate 320. The reflective pattern (not shown) mayprovide high brightness and uniformity surface light to the entirety ofthe liquid crystal display panel.

Optical sheets 340, 350, and 360 may be arranged on the top surface ofthe light guide plate 320. The optical sheets 340, 350, and 360 mayoverlap the light guide plate 320. The optical sheets 340, 350, and 360may include a diffusion film 340, a prism film 350, and a protectivefilm 360. The diffusion film 340 contains diffusion particles such asbeads in order to spread light at the top of the light guide plate 320.The prism film 350 has a prism pattern that is formed at the top surfaceof the prism film 350 to focus light above the diffusion film 340. Theprotective film 360 is layered on the top of the prism film 350 toprotect the prism film 350. The prism film 350 may improve brightness ofthe light. The optical sheets 340, 350, and 360 diffuse and focus lightthat is guided by the light guide plate 320 after being emitted from thelight emitting device packages 312, thereby achieving desired brightnessand viewing angle.

The diffusion film 340 scatters and focuses light incident from thelight emitting device packages 312 or returned light reflected from theprism film 350 to achieve uniform brightness.

The diffusion film 340 may be formed of transparent resin in the form ofa thin sheet. For example, the diffusion film 340 may be formed bycoating resin for light scattering and focusing on a polycarbonate orpolyester film.

The prism film 350 includes a prism pattern that is formed horizontallyor vertically on a surface of an optical film to focus light emittedfrom the diffusion film 340.

The prism pattern of the prism film 350 may be formed so as to have atriangular cross-section in order to increase focusing efficiency. Theprism film 350 achieves highest brightness when using a right-angledprism having a vertical angle of 90°.

The protective film 360 may be layered on the top of the prism film 350to protect the prism film 350.

The reflection sheet 330 is formed at the bottom (i.e., rear surface) ofthe backlight unit 300 and reflects light generated by the lightemitting device packages 312 toward the front of the backlight unit 300to increase light transfer efficiency.

FIG. 6E is a partial cross-sectional view of a backlight unit accordingto another embodiment.

As shown in FIG. 6E, the light emitting device array 310 includes asubstrate 316 having a first region 31 and a second region 32 and lightemitting device packages 312 arranged on the substrate 316.

The first region 31 and the second region 32 may be inclined at an anglebetween 90° and 160° with reference to each other. A first lightemitting device package may be arranged on the first region 31 and asecond light emitting device package may be arranged on the secondregion 32. Although the first light emitting device package and thesecond light emitting device package may be the same light emittingdevice packages, the first and second light emitting device packages mayhave different sizes or may emit light of different colors in someembodiments as described above in the embodiment of FIG. 4.

The light emitting device package arranged on the first region 31 mayemit light to a corner of the light guide plate 320. The light emittingdevice array 310 emits light at two angles to the light guide plate 320,thereby minimizing the occurrence of a dark zone on the top surface ofthe light guide plate 320.

FIG. 7A is a partial cross-sectional view of a backlight unit accordingto an embodiment, FIG. 7B is a partial cross-sectional view of abacklight unit according to an embodiment, and FIG. 7C is a partialcross-sectional view of a backlight unit according to an embodiment.

As shown in FIG. 7A, a reflective pattern 422 may be formed on thebottom surface of a light guide plate 420. The reflective pattern 422may be formed on the bottom surface of the light guide plate 420 toachieve uniform surface light.

The reflective pattern 422 may be provided at the bottom surface of thelight guide plate 420. The reflective pattern 422 may irregularlyreflect light incident on the light guide plate 420 to direct the lightto the top surface of the light guide plate 420.

The reflective pattern 422 may include a plurality of repeated figures.The interval between each pair of adjacent figures of the reflectivepattern 422 may decrease as the distance between the pair of adjacentfigures and the light emitting device array 410 increases. The area ofeach figure of the reflective pattern 422 may increase as the distancebetween the figure and the light emitting device array 410 increases.

The reflective pattern 422 may control the intensity of light reflectedto the top surface of the light guide plate 420. The interval betweeneach pair of adjacent figures of the reflective pattern 422 may beadjusted to control the intensity of light reflected to the top surfaceof the light guide plate 420. Figures of the reflective pattern 422 maybe arranged more closely to reflect a greater intensity of light to thetop surface as the distance between the figures and the light emittingdevice array 410 increases.

The reflective pattern 422 may be approximately in the form of an arc.The reflective pattern 422 may be in the form of a curve. The reflectivepattern 422 may be in the form of an array of curves. The reflectivepattern 422 may be in the form of arcs. The reflective pattern 422 maybe in the form of arcs which are centered on a corner of the light guideplate 420 which is adjacent to the light emitting device array 410. Thereflective pattern 422 may also be in the form of parts of a circlewhich is centered on the corner of the light guide plate 420.

Such arcs of the reflective pattern 422 may convert light incident onthe light guide plate 420 into surface light. The reflective pattern 422may minimize the influence which a decrease in the intensity of light asthe distance from the light emitting device package 412 increases hasupon the uniformity of the surface light.

Referring to FIG. 7B, a backlight unit 400 according to an embodimentmay include two substrates 416.

Two light emitting device arrays 410 may be arranged at two differentcorners of the light guide plate 420. When the backlight unit 400includes a plurality of light emitting device arrays 410, it is possibleto increase the intensity of light incident on the light guide plate420.

According to an embodiment, the light guide plate 420 may include fourcorners (or corner edges) between the side surfaces thereof. Each of thetop and bottom surfaces of the light guide plate 420 may take the formof a quadrangle as shown in FIG. 7B.

The light emitting device arrays 410 may be arranged respectively at twodiagonally opposite corners of the light guide plate 420. A bent portion414 of each of the light emitting device arrays 410 may be arranged at acorner of the light guide plate 420. A surface of the light emittingdevice array 410 on which light emitting device packages 412 areprovided may face one side surface of the light guide plate 420. Thelight emitting device array 410 may include light emitting devicepackages 412 to eliminate a dark zone that may occur on the light guideplate 420. A plurality of light emitting device arrays 410 may bearranged facing each other to emit light to a plurality of side surfacesof the light guide plate 420 to improve the intensity of light of thebacklight unit 400.

The reflective pattern 422 according to an embodiment may be formed onthe bottom surface of the light guide plate 420. The reflective pattern422 may include a line that intersects a virtual line connecting the twocorners at which the light emitting device arrays 410 are arranged. Forexample, the reflective pattern 422 may include a line that connects twocorners other than the two corners at which the light emitting devicearrays 410 of the light guide plate 420 are arranged. The reflectivepattern 422 may prevent light incident from two directions fromconcentrating upon a specific portion. The reflective pattern 422 mayallow luminance of the light guide plate 420 to be uniform at the centerand side portions thereof.

As shown in FIG. 7C, a backlight unit according to an embodiment mayinclude two light emitting device arrays 410. The light emitting devicearrays 410 may be arranged at two adjacent corners of the light guideplate 420. When the backlight unit includes a plurality of lightemitting device arrays 410, it is possible to increase the intensity oflight incident on the light guide plate 420.

The reflective pattern 422 may include a figure (for example, a line)that extends in a direction perpendicular to a line that connects twocorners of the light guide plate 420 that are adjacent to the lightemitting device arrays 410. The reflective pattern 422 may include aline that divides one quadrangle, which is the shape of the light guideplate 420 when viewed from the top, into two rectangles. The reflectivepattern 422 may include a figure that is formed to divide the lightguide plate 420 in the middle thereof.

The reflective pattern 422 may include a figure that is formed to dividethe light guide plate 420 into two rectangles to reduce the phenomenonof concentration of light incident from the light emitting devicepackages 412 of the light emitting device array 410 upon a specificportion. The reflective pattern 422 may allow the luminance of the lightguide plate 420 to be uniform at the center and side portions thereof.The reflective pattern 422 may reduce the phenomenon of concentration oflight, the intensity of which has been increased by adding lightemitting device packages 412, upon a specific portion.

FIG. 8 is a perspective exploded view of a liquid crystal display device500 including a backlight unit 570 according to an embodiment. Portionsthat have already been described above will not be described in furtherdetail.

In the embodiment of FIG. 8, the liquid crystal display device 500 maybe a liquid crystal display device of an edge light type which includesa liquid crystal display panel 510 and a backlight unit 570 thatprovides light to the liquid crystal display panel 510.

The liquid crystal display panel 510 may display an image using lightreceived from the backlight unit 570. The liquid crystal display panel510 may include a color filter substrate 512 and a thin film transistorsubstrate 514 that face each other with liquid crystal disposedtherebetween.

The color filter substrate 512 may add color to an image that is to bedisplayed through the liquid crystal display panel 510.

The thin film transistor substrate 514 is electrically connected to aprinted circuit board 518, on which a number of circuit parts aremounted, through a drive film 517. The thin film transistor substrate514 may apply a drive voltage received from the printed circuit board518 to the liquid crystal in response to a drive signal provided fromthe printed circuit board 518.

The thin film transistor substrate 514 may include thin film transistorsand pixel electrodes that are formed in thin films on anothertransparent substrate such as glass or plastic.

The backlight unit 570 may include light emitting device packages 524, alight guide plate 530, optical sheets 550, 560, and 564, and areflection sheet 540. The light emitting device packages 524 emit lightand the light guide plate 530 converts light provided from the lightemitting device packages 524 into surface light and provides the surfacelight to the liquid crystal display panel 510. The optical sheets 550,560, and 564 achieve a uniform brightness distribution of light providedfrom the light guide plate 530 and improve the vertical incidenceproperty. The reflection sheet 540 reflects light emitted from the rearsurface of the light guide plate 530 toward the front surface of thelight guide plate 530. A light source module 520 may include a pluralityof light emitting device packages 524 and a substrate 522 on which thelight emitting device packages 524 are mounted to constitute a lightemitting device array 520.

The substrate 522 of the backlight unit 570 according to an embodimentmay be formed obliquely at an inclination angle and arranged at a cornerof the light guide plate 530 which corresponds to an edge of one sidesurface of the light guide plate 530. The light emitting device packages524 provide light to two side surfaces of the light guide plate 530between which the corner of the light guide plate 530 is located,thereby preventing the occurrence of a dark zone in the light guideplate 530.

Using the substrate 522 according to the embodiment, it is possible toimprove the intensity of light emitted from the backlight unit 570 andto achieve optical reliability.

FIG. 9 is a cross-sectional view of an electronic device including abacklight unit (not shown) according to an embodiment.

Although a mobile communication terminal 600 is illustrated as anexample of the electronic device including the backlight unit (notshown) in the embodiment of FIG. 9, there is no limitation as to thetype of the electronic device including the backlight unit.

The mobile communication terminal 600 according to the embodiment mayinclude a receiver portion 680, a screen 660, operating keys 670, and acamera 610. The receiver portion 680 outputs an audio signal or the likeof the communication counterpart. The screen 660 may function as adisplay device. The operating keys 670 are used, for example, to startand end communication. The camera 610 is used, for example, to performvideo communication or to take a photograph. The screen 660 may includea touch panel such that the screen 660 may be used not only as a displaydevice but also as an input device.

A liquid crystal display device (not shown) may be provided inside thescreen 660 and the liquid crystal display device (not shown) may includea backlight unit (not shown).

The substrate (not shown) of the backlight unit (not shown) according toan embodiment may be obliquely arranged at an inclination angle andarranged at a corner of the light guide plate (not shown) whichcorresponds to an edge of one side surface of the light guide plate. Thelight emitting device packages (not shown) provide light to two sidesurfaces of the light guide plate (not shown) between which the cornerof the light guide plate is located, thereby preventing the occurrenceof a dark zone in the light guide plate (not shown).

Using the substrate (not shown) according to the embodiment, it ispossible to improve the intensity of light emitted from the backlightunit (not shown) and to achieve optical reliability.

In the light emitting device array according to an embodiment, a lightemitting device package that is arranged adjacent to one edge of thesubstrate is formed obliquely, and therefore it is possible to preventthe occurrence of a dark zone at the edges of the substrate.

In addition, the light emitting device array according to an embodimentincludes light emitting device packages arranged such that light emittedfrom a light emitting device package, which is arranged adjacent to oneedge of the substrate and which is formed obliquely, overlaps lightemitted from a light emitting device package adjacent to the lightemitting device package, and therefore it is possible to reduce thetotal number of light emitting device packages arranged on the substrateand to increase light emission efficiency.

Further, the backlight unit according to an embodiment includes a lightemitting device array that is bendable and therefore it is possible toeasily fix the light emitting device array at a corner of the lightguide plate.

Furthermore, the backlight unit according to an embodiment includes alight emitting device array that is provided at one corner of the lightguide plate and therefore it is possible to prevent the occurrence of adark zone at the four corners of the light guide plate.

Moreover, the backlight unit according to an embodiment includes apattern formed on the bottom surface of the light guide plate andtherefore it is possible to generate surface light that is uniform overthe entire surface of the light guide plate.

Although the disclosure has been illustrated and described above withreference to the specific embodiments, the disclosure is not limited tothe specific embodiments and it will be apparent to those skilled in theart that various modifications can be made to the embodiments withoutdeparting from the scope of the disclosure as disclosed in theaccompanying claims and such modifications should not be construed asdeparting from the spirit or scope of the disclosure.

What is claimed is:
 1. A light emitting device array comprising: asubstrate including a first region and a second region that are formedin a bent shape, and the first region of the substrate is inclined withrespect to the second region of the substrate, wherein the substratefurther includes a third region that is inclined with respect to thefirst region; a first light emitting device package disposed on thefirst region; a second light emitting device package disposed on thesecond region and inclining with respect to the first light emittingdevice package at an inclination angle between 90° and 160°, wherein thefirst light emitting device package faces a corner of a light guideplate that corresponds to an edge of one side surface of the light guideplate and provides light to the corner of the light guide plate; and athird light emitting device package that is arranged on the thirdregion, wherein the third light emitting device package faces a firstside of the light guide plate and the second light emitting devicepackage faces a second side of the light guide plate, the second side ofthe light guide plate being opposite the first side of the light guideplate.
 2. The light emitting device array according to claim 1, whereina size of the first light emitting device package is equal to or greaterthan a size of the second light emitting device package.
 3. The lightemitting device array according to claim 1, wherein a first separationdistance between the first light emitting device package and the secondlight emitting device package varies according to a size of the firstlight emitting device package or the second light emitting devicepackage.
 4. The light emitting device array according to claim 1,wherein the first light emitting device package and the second lightemitting device package are of a side view type.
 5. The light emittingdevice array according to claim 1, wherein the second light emittingdevice package is a plurality of light emitting device packages, and thefirst separation distance between the first light emitting devicepackage and one of the second light emitting device packages that isadjacent to the first light emitting device package is equal to orlonger than a distance between the second light emitting devicepackages.
 6. A backlight unit comprising: a light guide plate; and atleast one light emitting device array arranged adjacent to a corner ofthe light guide plate that corresponds to an edge of one side surface ofthe light guide plate, the light emitting device array comprising: asubstrate includes a first region and a second region that are formed ina bent shape, and the first region of the substrate is inclined withrespect to the second region of the substrate, a first light emittingdevice package disposed on the first region, and a second light emittingdevice package that is disposed on the second region and is inclinedwith respect to the first light emitting device package at aninclination angle between 90° and 160°, wherein the first light emittingdevice package or the second light emitting device package faces thecorner of the light guide plate that corresponds to the edge of one sidesurface of the light guide plate and provides light to the corner of thelight guide plate; and a reflective pattern including an arc in a formof parts of a circle that is centered on the corner of the light guideplate, wherein the arc is adjacent to the light emitting device array.7. The backlight unit according to claim 6, wherein the first region isarranged to face the corner of the light guide plate.
 8. The backlightunit according to claim 6, wherein the substrate further comprises athird region that is inclined with respect to the first region, and thelight emitting device array further comprises a third light emittingdevice package that is disposed on the third region.
 9. The backlightunit according to claim 8, wherein the first region of the substrate isadjacent to the corner of the light guide plate.
 10. The backlight unitaccording to claim 6, wherein the reflective pattern is formed at abottom surface of the light guide plate.
 11. The backlight unitaccording to claim 6, wherein the reflective pattern comprises aplurality of pattern elements formed such that an interval between eachpair of adjacent pattern elements decreases as a distance between thepair of adjacent pattern elements and the light emitting device arrayincreases.
 12. The backlight unit according to claim 6, wherein thereflective pattern comprises a plurality of pattern elements formed suchthat an area of each pattern element increases as a distance between thepattern element and the light emitting device array increases.
 13. Thebacklight unit according to claim 6, wherein the light emitting devicearray comprises at least two light emitting device arrays that arearranged at different corners of the light guide plate.
 14. Thebacklight unit according to claim 13, wherein the light emitting devicearrays are arranged at corners of the light guide plate that correspondto edges of different side surfaces of the light guide plate.
 15. Thebacklight unit according to claim 14, wherein the reflective pattern isformed on a bottom surface of the light guide plate and the light guideplate includes a line that connects two corners other than the twocorners at which the light emitting device arrays of the light guideplate are arranged.
 16. The backlight unit according to claim 13,wherein the light emitting device arrays are arranged at two corners ofthe light guide plate that are connected by one side surface of thelight guide plate.
 17. An image display device comprising: the backlightunit according to claim 6; and a liquid crystal display panel arrangedon the backlight unit, the liquid crystal display panel comprising acolor filter substrate and a thin film transistor substrate that faceeach other.